The present invention concerns a construction element containing plaster for use in ceilings or vertical elements, the doubling of partition-walls, and in general for the equipping of any building structure.
It is known from French Pat. No. 2 376 272 how to set up dry partitions by means of plaster panels covered with cardboard along two opposite parallel faces of the panel with the faces being articulated around a hinge formed by one of the thicknesses of the cardboard capable of being folded back at a right angle to form a brace. In order to render the faces foldable, a groove is made in the thickness of the plaster, taking care to leave intact the cardboard cover on one side so that it may serve as a hinge.
But the failure of the plaster to hold when the cardboard cover is weakened or has disappeared as a result of moisture, or fire, or handling without precautions, the need of a finishing treatment of the cardboard surface, the need to improve the resistance to shocks, led to the manufacture of panels without cardboard, reinforced in all their thickness or at least in the greater part of their thickness, for instance by glass fiber, and displaying the same finish as the traditional plaster cover. It is no longer a question, in such panels, to make a groove to allow the folding back of the faces, without at the same time automatically cutting all or part of the reinforcement, for example, glass fibers, placed in the interior of the panels themselves. Moreover, when these reinforcements are distributed in all the thickness, or even only in a certain portion of the thickness, or if they are arranged at several levels in the thickness, the folding of the faces places those situated on the outside of the fold in tension and makes them break and/or break away from the matrix which they are meant to reinforce.
The present invention proposes construction elements in plates, particularly in plaster, comprising reinforcements distributed in all their thickness, in which the reinforcements are concentrated in a predetermined zone of the thickness along fold lines parallel to the sides of the plates.
Advantageously, these reinforcements are concentrated along these fold lines, until they form but a single plane of reduced thickness in the very thickness of the reinforcements.
In a manner of preferred realization, the plaster is eliminated along these fold lines.
The present invention concerns plaster plates reinforced by natural or artificial fibers, textile threads, organic or mineral fibers, weavings, non-weavings, glass fibers, metallic fibers, lattices formed with the previously mentioned fibers, fiber sheets, for instance of continuous tangled-up glass, or by combinations of these different reinforcements, thus, for example, preferentially by a sheet of continuous entangled glass fibers covered above and below by one or several glass fiber lattices.
In one mode of the invention, the fold lines are parallel.
In one advantageous mode of the invention, the various constituent panels of the plates are separated by the fold lines and are folded back in relation to one another so as to form a non-planar construction element.
In another mode of the preferred invention, the construction elements have two fold lines delimiting a principal panel and two secondary panels or flaps arranged each on one side of the main panel, the said flaps being raised above the plane of the main panel, approximately at an angle of 90.degree., in such a way as to form a U-shaped trough. Advantageously, in order to obtain a good resistance to flection of the construction elements thus obtained, the flaps have a height which is in the range of 1/40th of the width of the main panel of said construction elements.
The construction elements in the form of trough are capable of being used in ceilings, and may be associated by jointing.
When only a juxtaposition of the trough is preferred, the fold lines preferably are in a plane situated at the level or in the vicinity of the lower visible face of the troughs.
When it is preferred to joint with a coating, the plane of the fold lines shall on the contrary be brought appreciably to mid-thickness of the main panel and the flaps of the trough form with the main panel a slightly obtuse angle in the range of 95% so as to permit the jointing by a sufficient thickness of coating.
Advantageously, these construction elements carry insulation.
In order to fabricate such construction elements, a plate is formed by casting a liquid mixture of plaster and water and a reinforcement is introduced in the said mixture. The reinforcement is concentrated in a single plane parallel to the plane of the casting along certain fold lines, and the reinforcement is held in position along these fold lines during the evolution of the setting of the plaster until that position holds by itself. The plaster is then driven out plumb with these fold lines and one folding effected.
The positioning of the reinforcement along the fold lines may be modified before the mixture attains a consistency which corresponds to the F.L.S. 100 fluidity and the modifying action is maintained at least until the mixture has a fluidity of F.L.S. close to 60.
Preferentially, the plaster is removed from around the fold lines at least from the moment when the mixture has the F.L.S. 60 fluidity.